The present invention relates to a process for activating or sensitizing the surfaces of plastic materials by chemical nucleation with a noble metal so that a metallization can be performed thereafter.
When metallizing plastics, such as acrylonitrilebutadiene-styrene (hereinafter referred to as ABS) or modified Plexiglas materials, it is customary to acitvate the surface, after it has been roughened mechanically, by means of a strong oxidation agent, e.g. hot SO.sub.3 vapor, in order to then be able to nucleate the surface with a noble metal. After being activated with noble metal nuclei, the plastic surfaces may then be metallized, e.g., with copper, nickel, silver, gold, the metals being chemically deposited on the noble metal nuclei. The above explained measures are called the SAN method.
While the so-called SAN method results in the formation of adherent metal coatings on plastic surfaces, the method is characterized by several disadvantages. For example, one disadvantage of this method is that the SO.sub.3 vapor is not only very toxic, but it is also very corrosive. This requires considerable expenditures for equipment in order to keep environmental pollution within limits and to prevent any danger to the health of the personnel operating the plant.